Methane dyes and their preparation



Patented Oct. 24, 1950 I p UNITED, STATES PATENT OFFICE 2,527,264 METHANE DYES AND THEIR PREPARATION John David Kendall and Harry Derek Edwards, Ilford, England, assignorsto Ilford Limited, Ilford', England, a British company No Drawing. Application August 5, 1947, Serial No. 766,454. In Great Britain August 13, 1946 12 Claims. (Cl. 260- 307 This invention relates to the production of particularly, according to the invention, the solmethane dyes and particularly to the production ventis liquid ammonia.

of dyes which are tri-heterocyclo substituted .;It'is believed that the reaction proceeds in two methanes. stages thus: I

'Scheibe and Rossner have described in 'Be- 5 Stage 1 richte der Deutschen Chemischen Gesellschaft, volume 53 at page 2064 (1920), a method of producing tri-quinolyl(2)-methane by heating together quinaldine and 2-chlorquinoline. In this a I reaction it appears that one molecule of quinal- 10 dine reacts with two molecules of 2-chlorquinoline with the elimination of two molecules "of We have attempted to extend this reaction, one of hydrogen atoms on t central using Scheibe and Rossners reaction conditions. 15 carbon P 13 then replaced by amah'memIand However, using one molecular equivalent of "1- the reactlon proceeds thus: methyl benzthiazole and two molecular equiv-v Stage 2 alents of 2-chlorbenzthiazole, no tri-benzthiazolyl-methane could be isolated. Similarly, using one molecular equivalent of l-methyl benzthia- 29 N=(CH'CH)"=CCHMC=(CH OH)"=N+xczwH'om'FN zole and two molecular equivalents of 2-chlorl quinoline, no benzthiazolyl-diquinolyliZ)-methane could be isolated. It is thus clear that the Scheibe and Rossner conditions arenot practical for the production of other tri-heterocyclometh- 9 m M '1! C(OH ane compounds 'N=(CHCH) n=C-CH\ Dz- 1;

It will be observed that the Scheibe and Ross- C=,(OH-CH) .=1'\* ner process relies on ,the use of a free hetero cyclic nitrogen base containing a. reactivemeth'yl group in a. or 7 position tothe heterocyclio nitro- 39 gen atom. It has J now been discovered that .if instead of using the free .heterocyclic nitrogen base containing the reactive methyl group in a or 7 position to the heterocyclic nitrogen atomv there is employed an alkali-metal derivative of 3;, such base, the reaction preferably being carried,

In the foregoing formulae D1 and D2 are the residues of heterocyclic nitrogen compounds, M' is an atom of an alkali-metal, X is a halogen and n is nought or one.

The-heterocyclic nitrogen bases employed in this invention, i. e. the rings of which D1 and. D2 form part, may be, for example, thiazoles, oxazoles,:selenazoles and their polycyclic homologues out in a cooled solvent such as liquid ammonia, naphthene and anthracene series, pyridine and the reaction takes place vigorously .to form the itsypolycyclic homolggues such as quinolin d tri-heterooyclo-methanes in satisfactory yield; nd p-naphthaquinolines, 'lepidines, i d 1 Ac ord t e p e invention, therefore, to nines, diazoles such as pyrazoles, imidazoles and a p s r the p du n of methane d s thio-pfi-diazble, diazines such as pyrimidines comprises leactingmgether an alkali-metal Saltand quinazolines, thiazolines, oxazolines and Of a heterocyclic nitrogen base Containing a :r selenazolines. The polycyclic compounds of thesev active methyl group in a. or 7 position tothe series may also be substituted in the carheterocyclic nitrogen atom with a heterocyclic e5 bocyclic rings with alkyl, aralkyl or aryl groups, nitrogen base containing a halogen atom in a or 7 .alkoxy or amino groups, or halogen atoms.

position to the heterocyclic nitrogen atom. Pref- :Th'e halogen atom .X may be chlorine, bromine erably the reaction is effected in a solventin or;iodine, but chlorine is generally preferable as which the reactants can ionize but which does the chlorintermediates are thesimplestto make. not decompose the alkali-metal ,sa-ltand amore, 50 Although, as indicatedby the above formulae,

suchas those of the benzene, naphthalene, acethe reaction requires two molecular equivalents of the halogen compound to one of the reactive methyl compound, it is not, in fact, necessary metal to liquid ammonia, forming the alkali-metal I amide (e. g. sodamide or potassamide) and then to add to this reaction mixture first the heterocyclic compound containing the reactive methyl group and then the heterocyclic compound containing the halogen atom.

The following examples illustrate the invention:

EXAMPLE 1 Preparation of tri-benzthiazolyl (1) -metizane 0.92 part by weight of sodium were dissolved in 50 parts by weight of liquid ammonia, and a small quantity of ferric nitrate added-as catalyst. The

flask was maintained cold by immersion in a'bath containing alcohol and solid carbon dioxide. 2.98 parts by weight of l-methyl benzthiazole, were then added with mechanical stirring, the stirring continued for ten minutes and then 6.75 parts by weight of l-chlor benzthiazole was added, the stirring being continued for a further ten minutes.

The flask was then removed from the cooling bath, 50 parts by weight of ether was added and the ammonia allowed to evaporate at room temperature. The ether was then removed and the residue washed with water and ethyl alcohol and then recrystallised from benzene. The product consisted of pale yellow needles melting at 271 C.

EXAMPLE 2 Preparation ,f benzthiazolyl (1)-dz [benzoxaeolyZ (1). -methane The procedure of Example 1 was followed except that the l-methyl benzthiazole was replaced by 6.11 parts by weight of l-chlor benzoxazole. The product after recrystallisation from benzene consisted of a pale yellow solid melting above 280 C.

EXAMPLE 3 Preparation of quinolyl (2) -di[benzthiazolyl 1) methane The procedure of Example 1 was followed except that l-methyl benzthiazole was replaced by 2.86 parts'by weight of quinaldine. The product after recrystallisation from ethyl alcohol consisted of red crystals melting at 190 C.

EXAMPLE 4 Preparation of qainolyl (4) -di[benethiazo=lyl 1) lmethane EXAMPLE 5 Preparation of thiazolinyl (2) -di[benzthiazolyl (1) l-methane The procedure of Example 1 was followed except that the l-methyl benzthiazole was replaced by 2.02 gm. of -methyl thiazoline. The product consisted of pale yellow crystals sparingly soluble in both ethyl and methyl alcohol.

EXAMPLE 6 Preparation of benzthiazolyl (1)-di[quinolyl( 4)]- methane The procedure of Example 1 was followed except that the l-chlor benzthiazole was replaced by 6.25 gm. of l-chlorquinoline and that the ammonia was allowed to evaporate overnight, the product being isolated by benzene extraction from the residue. After crystallisation from ethyl alcohol the compound was obtained as colourless crystals, M, P. 264 C.

Analysis: CzsHmNzS- requires S=7.92%; found, S=8.02%.

Many of the tri-heterocyclo-methane dyes of this invention are valuable sensitisers for silver halide photographic emulsions, e. g. silver iodide,"

silver bromide, silver chloride, silver iodobromide and silver chlorobromide gelatin emulsions, the increased sensitivity usually being imparted in the blue and/ or green regions of the spectrum. Thus,

for example, the product of Example 2, includedin'a gelatino silver iodobromide emulsion,imparts I a band of sensitivity extending to 5800 A. with a maximum at 5400 A, and the product of Example 5, included in a gelatino silver chloride emulsion, imparts a band of sensitivity with a maximum at 4300 A.

What we claim is:

1. A process for the production of methane. dyes which comprises reacting together an alkalimetal salt of a heterocyclic nitrogen base containing a reactive methyl group in one of the positions a and 'y to the heterocyclic nitrogen atom with a heterocyclic nitrogen base containing a halogen atom in one of the positions a and 'y to the heterocyclic nitrogen atom, the reaction being efiected in liquid ammonia. v

2. A process for the production of methane dyes which comprises reacting together a sodium salt of a heterocyclic nitrogen base containing a reactive methyl group in one of the positions a and. to the heterocyclic nitrogen atom with a heterocyclic nitrogen base containing a halogen atom in one of the positions a and 'y to the heterocyclic nitrogen atom, the reaction being efiected in liquid ammonia.

3. A process for the production of methane dyes which comprises reacting together an alkali-metal salt of a heterocyclic nitrogen base containing a reactive methyl group in one of the positions a and 'y to the heterocyclic nitrogen atom with l-chlorbenzthiazole, the reaction being efiected in liquid ammonia. 4. A process for the production of methane dyes which comprises reacting together an alkali-'' metal salt of a heterocyclic nitrogen base containing a reactive methyl group in one of the positions a and 'y to the heterocyclic nitrogen atom with l-chlorbenzoxazole, the reaction being efi'ected in liquid ammonia.

5. A process for'the production of methane dyes which comprises dissolving an alkali-metal in liquid ammonia, adding thereto a heterocyclic nitrogen'base containing a reactive methyl group in one of the positions cc and 'y to the heterocyclic nitrogen atom and then adding a heterocyclic nitrogen base containing a halogen atom in one of the positions on and v to the heterocyclic nitrogen atom.

6. A process for the production of methane dyes which comprises dissolving an alkali-metal in liquid ammonia, adding thereto a heterocyclic nitrogen base containing a reactive methyl group in one of the positions on and v to the heterocyclic nitrogen atom and then adding a l-chlorbenzthiazole.

7. A process for the production of methane dyes which comprises dissolving an alkali-metal in liquid ammonia, adding thereto a heterocyclic nitrogen base containing a reactive methyl group in one Of the ositions or and v to the heterocyclic nitrogen atom and then adding a l-chlorbenzoxazole.

8. A process for the roduction of methane dyes which comprises dissolving sodium in liquid ammonia, adding thereto a heterocyclic nitrogen base containing a reactive methyl group in one of the positions or and 'y to the heterocyclic nitrogen atom and then adding a l-chlorbenzthiazole.

9. A process for the production of methane dyes which comprises dissolving sodium in liquid ammonia, adding thereto a heterocyclic nitrogen base containing a reactive methyl group in one of the positions a and 'y to the heterocyclic nitrogen atom and then adding a l-chlorbenzoxazole.

10. Methane dyestufis of the general formula:

"Dio= o11oH).=N N= oHcH ..=ooH --D- C=(CHCH),.=N wherein D1 is the residue of a heterocyclic nitrogen compound and D2 is the residue of benzoxazole.

11. A process for the production of methane dyes which comprises reacting together an alkali-metal salt of a heterocyclic nitrogen base containing a reactive methyl group in one of the positions a and 'y to the heterocyclic nitrogen atom with a heterocyclic nitrogen base containing a halogen atom in one of the positions a: and v to the heterocyclic nitrogen atom, the reaction being eifected in liquid ammonia and in the presence of excess alkali metal.

12. A process for the production of methane dyes which comprises reacting together one molecular proportion of a sodium salt of a hetero- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,166,736 White et al. July 18, 1939 2,263,749 White et a1 Nov. 25, 1941 2,322,015 Hamer et al. June 15, 1943 2,340,882 Kendall Feb. 8, 1944 2,342,546 Kendall Feb. 22, 1944 2,353,164 Kendall July 11, 1944 2,478,367 Brooker et a1. Aug. 9, 1949 OTHER REFERENCES Berichte, vol. 53, pages 2064-2066 (1920).

Georgievics et al., A Text-book of Dye Chemistry, 1920, page 168 (Scott-Greenwood 8: Son, publisher).

Chemical Abstracts, 1613101 (Abstract of Brit. Med. Journal, 1922 I 514-515).

Chemical Abstracts, 19:530 (Abstract of Proc. Roy Soc, London, 963 317-333, 1924). 

1. A PROCESS FOR THE PRODUCTION OF METHANE DYES WHICH COMPRISES REACTING TOGETHER AN ALKALIMETAL SALT OF A HETEROCYCLIC NITROGEN BASE CONTAINING A REACTIVE METHYL GROUP IN ONE OF THE POSITIONS A AND $ TO THE HETEROCYCLIC NITROGEN ATOM WITH A HETEROCYCLIC NITROGEN BASE CONTAINING A HALOGEN ATOM IN ONE OF THE POSITIONS A AND $ TO THE HETEROCYCLIC NITROGEN ATOM, THE REACTION BEING EFFECTED IN LIQUID AMMONIA.
 10. METHANE DYESTUFFS OF THE GENERAL FORMULA: 